Unmanned Air Vehicles (UAVs) are commonly used in surveillance operations.
Typically, UAVs tend to use gimballed cameras (i.e. cameras mounted on moveable turrets) for reconnaissance.
However, only a small area of interest can be observed at any moment in time using such an approach. Furthermore, gimballed cameras tend to adversely affect the aerodynamic profile of an aircraft upon which it is mounted, e.g. by increasing drag.